Normally, the serial number profile is plant specific and hence it is in MARC, not in MARA. If the field MARA-SERIAL is already activated in your system or if you want to update the serial number profile at plant level, proceed as follows.

Go to MASS transaction. Select object type BUS1001 and execute. Now, click on fields tab. Find the field (MARA-SERIAL or MARC-SERNP ) for serial number profile (or any other required field). Select the field and execute. Enter the required material numbers and plants and execute. Enter the serial number profile on the header and click on mass change. icon